1. Field of the Invention
This invention relates to a lamp for a vehicle and more particularly constitution of the lamp for the vehicle such as a headlamp and a fog lamp used for (the purpose of) illuminating, and the object of the invention is to provide the constitution capable of improving an utilization factor of luminous flux for a light source and allowing a light-distribution characteristic to be variable. Moreover, this invention relates to a headlamp which is installed on the vehicle and more particularly to constitution of the headlamp in which a light distribution for a low beam is made it possible to switch from and/or to a light distribution for an upper beam using a light source such as a metal halide discharge lamp which does not have both of a filament for a low beam and the filament for the upper beam, for example.
2. Detailed Description of the Prior Art
A prior constitution of a headlamp 90 of this type represented as an example in the case where a light source 91 is a metal halide discharge lamp or the like and the headlamp 90 is a exclusive-light distribution for a low beam is shown in FIG. 22, and FIG. 23, and a parabolic-reflecting surface 92 formed into a paraboloid of revolution or the like having a focus xe2x80x9cfxe2x80x9d in a rearward position is provided with respect to an arc 91a of said light source 91.
According to this constitution, since an downward light beam would be generated from a upper half portion of the parabolic-reflecting surface 92, and an upward light beam from a lower half portion, said light source 91 (the arc 91a) is provided with a shield plate 93 on the lower, thereby light to be shielded so as to not reach the lower half portion of the parabolic-reflecting surface 92. Moreover, said light source 91 also is provided with a stripe 91b by black opaque paint or the like and the stripe 91b serves a part of functions of said shield plate 93. In addition, said shield plate 93 is provided with a shade shielding a direct light.
According to this constitution, the light comes to reach only the upper half portion of said parabolic-reflecting surface 92, that is, most of the light becomes the downward light beam, and the light distribution for the low beam can be obtained as shown in FIG. 23. Moreover, the portion which the light of a part of the lower half portion of the parabolic-reflecting surface 92 reaches is a portion for forming a light distribution referred to as an elbow, which illuminates the side of the roadside zone with an appropriate upper light beam in order to facilitate to recognize visually a road sign or the like installed on a roadside zone in FIG. 23.
Moreover, the prior headlamp 90 having the constitution of the headlamp in which the light distribution for the low beam is made possible to switch from and/or to the light distribution for the upper beam using the light source which does not have both of a filament for a low beam and the filament for the upper beam is shown in FIG. 24 to FIG. 25, and the light source 91 are provided with the shade 92 for preventing for the direct light from this light source 91 from irradiating the portion other than the headlamp 90 and to become a glare light, as well as a movable shield plate 93 which can be set at two positions by a driving device 96 such as a solenoid, for example.
Moreover, the central portion of a reflecting mirror 94 provided in the rearward position of said light source 91 is formed into a main reflecting portion 94a, the upper thereof is formed into an auxiliary reflecting portion 94b, and the side surfaces of the right and left thereof is formed into an auxiliary reflecting portion 94c as shown in the drawings. Moreover, the lower is provided with a shield plate 95 since the light colored with yellow or the like would be irradiated when said light source 91 is the metal halide discharge lamp, and the reflecting mirror 94 can not be provided on the lower of the light source 91 with exception of a part required for forming the light distribution.
Moreover, said main reflecting portion 94a is formed into the paraboloid of revolution or the like having a focus in appropriate front of the light source 91, whereby the downward reflected-light is generated, and said auxiliary reflecting portion 94b and the auxiliary reflecting portion 94c are formed into the paraboloid of revolution or the like which has a focus at the light source 91, whereby the reflected light traveling in the horizontal direction is generated.
Moreover, said movable shield plate 93 shields the portion which would reach said auxiliary reflecting portion 94b and auxiliary reflecting portion 94c, of the light from the light source when the driving device 96 is not operated, whereas the movable shield plate 93 allows the light to launch into the entire surface of the reflecting mirror 94, that is, both of the main reflecting portion 94a and the auxiliary reflecting portion 94b, 94c when the driving device 96 is operated.
According to this constitution, the light distribution of the headlamp 90 is constituted by only the downward light from the main reflecting portion 94a as shown by a light distribution xe2x80x9cSxe2x80x9d in FIG. 26 when the driving device 96 is not operated, that is, becomes the light distribution for the low beam. A light distribution H1 to the horizontal direction from the auxiliary reflecting portion 94b and a light distribution H2 from the auxiliary reflecting portion 94c are added to the light distribution xe2x80x9cSxe2x80x9d when the driving device 96 is operated, and the light distribution for the upper beam can be obtained by synthesizing the light distribution xe2x80x9cSxe2x80x9d, the light distribution H1 and the light distribution H2.
Moreover, at this point of time, said light distribution H1 is formed so as to illuminate the front of the vehicle like as a spot by the auxiliary reflecting portion 94b provided on the upper of the main reflecting portion 94a that a reflection image of the light source 91 is elongated in the vertical direction, on the other hand, the light distribution H2 is formed so as to illuminate the right and left of the traveling direction of the vehicle widely by the auxiliary reflecting portion 94c provided on the sides of the right and left of the main reflecting portion 94a that the reflection image of the light source 91 is elongated in the horizontal direction.
However, the utilization factor of luminous flux with respect to the light source 91 has been essentially low in the headlamp 90 according to the prior constitution described above, since only a substantial half of the parabolic-reflecting surface 92 is utilized in order to obtain the light distribution for the low beam. In addition thereto, there has been a problem in recent years that requirements or the like reducing a dimension of the up-and-down direction is increased for example, and it leads to reduction in square measure of said parabolic-reflecting surface 92, so that lack of illuminance of the headlamp 90 becomes noticeable increasingly due to the recognition that the headlamp 90 also supports a part of design of the vehicle. Moreover, there has been a problem in the headlamp 90 according to the prior constitution described above that the reflecting mirror 94 is compartmentalized into the main reflecting portion 94a and the auxiliary reflecting portion 94b, and the light distribution for the low beam used in most situation of the case of usual driving becomes dark since the auxiliary reflecting portion 94b is covered from the light source 91 in the case of the light distribution for the low beam.
This invention solves the problems by providing:
a headlamp constituted by providing on a substantial upper half portion a main reflecting surface formed into a parabolic surface providing a light-emitting source of a bulb as a substantial focus, wherein a right elliptic reflecting surface and a left elliptic reflecting surface providing the vicinity of a light-emitting source of a bulb as a primary focus respectively are provided on a position toward the front upper of the bulb in the form of being connected substantial along a center line of this headlamp, a second focus of said right elliptic reflecting surface being provided on the appropriate right side of said bulb, a second focus of said left elliptic reflecting surface being provided on the appropriate left side of said bulb, a right parabolic reflecting surface providing the second focus of said right elliptic reflecting surface as a focus is provided on a position toward the lower and right of said main reflecting surface, and a left parabolic reflecting surface providing the second focus of said left elliptic reflecting surface as a focus is provided on a position toward the lower and left of said main reflecting surface;
a headlamp constituted by providing on a substantial upper half portion a main reflecting surface formed into a parabolic surface providing a light-emitting source of a bulb as a substantial focus, wherein a right elliptic reflecting surface and a left elliptic reflecting surface providing the vicinity of a light-emitting source of a bulb as a primary focus respectively are provided on a position toward the front upper of the bulb in the form of being connected substantially along a center line of this headlamp, a second focus of said right elliptic reflecting surface being provided on the appropriate right side of said bulb, a second focus of said left elliptic reflecting surface being provided on the appropriate left side of said bulb, a right parabolic reflecting surface providing the second focus of said right elliptic reflecting surface as a focus is provided on a position toward the lower and right of said main reflecting surface, and a left parabolic reflecting surface providing the second focus of said left elliptic reflecting surface as a focus is provided on a position toward the lower and left of said main reflecting surface, and optical paths of the reflected light from said right parabolic reflecting surface and left parabolic reflecting surface are designed to be substantially parallel each other, or to intersect each other at front of the headlamp, as well as at least a part of the optical paths from said two parabolic reflecting surfaces is provided with a light-distribution varying means constituted by reflecting means or refracting means;
a headlamp constituted by providing on a substantial upper half portion a main reflecting surface formed into a parabolic surface providing a light-emitting source of a bulb as a substantial focus, wherein a right elliptic reflecting surface and a left elliptic reflecting surface providing the vicinity of a light-emitting source of a bulb as a primary focus respectively and each is formed into at least one piece are provided on a position toward the front upper of the bulb in the form of being connected substantially along a center line of this headlamp, a second focus of said right elliptic reflecting surface being provided on the appropriate right side of said bulb, a second focus of said left elliptic reflecting surface being provided on the appropriate left side of said bulb, at least a lower right reflecting surface which an ellipsoid providing the second focus of said right elliptic reflecting surface as a primary focus appears on a horizontal section on a position toward the lower and left of said main reflecting surface, and
at least a lower left reflecting surface which the ellipsoid providing the second focus of said left elliptic reflecting surface as the primary focus appears on the horizontal section on the position toward the lower and right of said main reflecting surface; and
a headlamp constituted by providing on a substantial upper half portion a main reflecting portion which is formed into a parabolic surface providing a light-emitting source as a substantial focus and forms a light distribution for the low beam, wherein the right and left of said main reflecting portion are provided with an auxiliary reflecting portion providing an irradiating direction as the front, and the front upper of said light source is provided with two elliptic reflecting surfaces providing said light source as a primary focus in a manner to stand face to face each other, and a second focus of these elliptic reflecting surfaces is provided at the vicinity of a side direction of said light source of the side in which the respective elliptic reflecting surface exists, and providing the second focus of said respective elliptic reflecting surface as a focus and a parabolic reflecting surface providing the irradiating direction as the front is provided on the lower of said main reflecting portion respectively, as well as the vicinity of said light source is provided with a movable shield plate, whereby light which is incident on said auxiliary reflecting portion from said light source and light which is incident on the parabolic reflecting surface from said elliptic reflecting surface can be designed to pass through and to be shielded; as specified means for solving the prior problems described above.